1. Field of Invention
This invention pertains generally to threaded fasteners and, more particularly, to a locking retainer for preventing threaded fasteners such as the cap screws which secure the end caps of roller bearing assemblies to the axles of railroad cars from working loose.
2. Related Art
Roller bearing are commonly mounted on the axles which carry the total weight of railroad cars and locomotives, with end caps retaining lubricant and holding the bearings in position on the axles. The end caps are attached to the axles by cap screws which must be tightened to the proper torque and provide adequate clamp load to ensure correct alignment and lubrication of the bearings. Otherwise, the bearings may become damaged, requiring unscheduled maintenance, and in the worst case, cause a derailment.
After the cap screws are tightened to the desired torque, tabs on current locking plates are bent against the heads of the screws to prevent them from working loose and turning. However, the screws can still work loose and turn, especially if the tabs break off or do not squarely engage the flat faces of the screw heads. Moreover, when the screws are turned to bring the flat faces into parallel alignment with the tabs, the screws may exceed the proper torque, which can lead to bearing failure and potential derailment of the train.